   ;; optimize a project
   (println (->> (-compile "samples/hello/src" {})
                 (apply add-dependencies {})
-                (apply optimize {:optimizations :simple :pretty-print yes})))
+                (apply optimize {:optimizations :simple :pretty-print true})))
   )
 
 ;; Output

               new-requires (remove #(or (contains? deps %)
                                         (contains? (set requires) %))
                                    (cljs-deps (-requires js)))]
           (recur (concat (rest requires) new-requires) (assoc deps next-ns js)))
         (dependency-order (vals deps)))))))

(comment

  already exist."
  [opts requires]
  (let [index (js-dependency-index opts)]
    (letfn [(cljs-deps [coll] (remove #(contains? index %) coll))]
     (loop [requires (cljs-deps requires)
            deps {}]
       (if (seq requires)
